BUNOJ 4044

#include <iostream>

#include <string>

using namespace std;

typedef struct Node

{

    char data;

    Node *lchild,*rchild;

}Node,*Bitree;

Bitree creat(string s1,string s2)

{  

    if(s1.length()==0)

        return NULL;

    Node *root;

    root = new Node;

    root->data = s1[0];//第二次做，竟然忘家了 

    size_t pos = s2.find(s1[0]);

    root->lchild=creat(s1.substr(1,pos),s2.substr(0,pos));//从index开始，共num个字符，不是到第num 

    root->rchild=creat(s1.substr(pos+1),s2.substr(pos+1));

    return root;

}

void postorder(Node *root)

{

    if(root)

    {

        postorder(root->lchild);

        postorder(root->rchild);

        cout<<root->data;

    }

}

int main()

{

    int i,j,k;

    string s1,s2;

    while(cin>>s1>>s2)

    {

        Node *root;

        root = creat(s1,s2);

        postorder(root);

        cout<<endl;

    }

    return 0;

}